U.S. patent application number 13/694764 was filed with the patent office on 2014-07-03 for method and apparatus for automatic descaling of tankless water heaters.
The applicant listed for this patent is Jon R. Taylor. Invention is credited to Jon R. Taylor.
Application Number | 20140182624 13/694764 |
Document ID | / |
Family ID | 51015744 |
Filed Date | 2014-07-03 |
United States Patent
Application |
20140182624 |
Kind Code |
A1 |
Taylor; Jon R. |
July 3, 2014 |
Method and apparatus for automatic descaling of tankless water
heaters
Abstract
A novel method of descaling a water heating unit at least
including: a) selectively receiving a user-defined descaling
operation start date and time; b) monitoring for the advent of the
descaling operation start date and time; c) upon the arrival of the
descaling operation start date and time, automatically shutting off
the supply of heated water to the demand destination; d)
automatically pumping a stored descaling solution through the water
heating unit to dislodge scale deposits; e) automatically rinsing
the water heating unit to remove dislodged scale deposits and
descaling solution; f) discharging dislodged scale deposits and
descaling solution; g) restoring the supply of heated water to the
demand destination; and h) returning the water heating unit to
normal operation mode.
Inventors: |
Taylor; Jon R.;
(Indianapolis, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Taylor; Jon R. |
Indianapolis |
IN |
US |
|
|
Family ID: |
51015744 |
Appl. No.: |
13/694764 |
Filed: |
January 2, 2013 |
Current U.S.
Class: |
134/18 ;
134/57R |
Current CPC
Class: |
F28G 9/00 20130101; F24D
19/0092 20130101; C02F 2303/22 20130101 |
Class at
Publication: |
134/18 ;
134/57.R |
International
Class: |
B08B 9/08 20060101
B08B009/08 |
Claims
1. A method of descaling a water heating unit, said water heating
unit being adapted to receive unheated, potable water via a
cold-side input, and adapted to output heated water to the demand
destination via a hot-side output, said method comprising: a)
operating a water heating unit in a normal mode as a default; b)
via a programmable control module, selectively receiving a
user-defined descaling operation start date and time; c) via said
programmable control module, monitoring for the advent of the
descaling operation start date and time; d) via said programmable
control module, and upon the arrival of the descaling operation
start date and time, automatically shutting off the supply of
heated water to the demand destination, and automatically
activating a pump; e) via said pump, automatically pumping a stored
descaling solution through said water heating unit via said
cold-side input of said water heating unit and said hot-side output
of said water heating unit to dislodge scale deposits from said
water heating unit; f) via said pump, automatically rinsing said
water heating unit to remove dislodged scale deposits and to remove
descaling solution; g) discharging dislodged scale deposits and
descaling solution from said water heating unit; h) restoring the
supply of heated water to the demand destination; and i) returning
the water heating unit to normal operation mode.
2. The method of claim 1, wherein said water heating unit is of the
"tankless" variety.
3. The method of claim 1, further comprising: j) automatically,
operatively coupling the unheated, potable supply water to a
potable water input valve, said potable water input valve also
being operatively coupled to said cold-side input and operatively
coupled to said pump; k) automatically, operatively coupling the
output from the hot-side to a hot water output valve, said hot
water output valve being operatively coupled to said hot-side
output and operatively coupled to said pump; l) automatically
forming a descaling circuit between the hot-side, the pump, the
cold-side and the internal flow of the water heating unit during a
descaling operation; and m) automatically forming a rinsing circuit
between the potable water input, the cold-side, the internal flow
of the water heating unit, the hot-side and a rinse discharge valve
during a rinsing operation.
4. The method of claim 1, further comprising: n) automatically
disabling the descaling and rinsing circuits during normal
operation mode.
5. The method of claim 1, further comprising: operating the valves
via operatively coupled solenoids.
6. The method of claim 5, further comprising: energizing and
de-energizing said solenoids according to signals from said
programmable control module.
7. The method of claim 5, further comprising: energizing and
de-energizing said solenoids in response to an operatively coupled
power relay.
8. A system for descaling a water heating unit, said water heating
unit being adapted to receive unheated, potable water via a
cold-side input, and adapted to output heated water to the demand
destination via a hot-side output, which water heating unit
operates in a normal mode as a default, said system comprising: a
pump; a descaling solution source; a plurality of valves; a
programmable control module operatively coupled to said pump, said
descaling solution source, and said valves, said programmable
control module adapted to selectively receive a user-defined
descaling operation start date and time, monitor for the advent of
the descaling operation start date and time, and upon the arrival
of the descaling operation start date and time, automatically shut
off via at least one valve, the supply of heated water to the
demand destination, and automatically activate said pump; said pump
adapted to automatically pump stored descaling solution through
said water heating unit via said cold-side input of said water
heating unit and said hot-side output of said water heating unit to
dislodge scale deposits from said water heating unit, and further
adapted to automatically rinse said water heating unit to remove
dislodged scale deposits and to remove descaling solution; and said
programmable control module further adapted to cause said valves to
discharge dislodged scale deposits and descaling solution from said
water heating unit, restore the supply of heated water to the
demand destination, and return said water heating unit to normal
operation mode.
9. The system of claim 8, wherein said water heating unit is of the
"tankless" variety.
10. The system of claim 8, wherein said valves further comprise: a
potable water input valve operatively coupled to the unheated,
potable supply water to a potable water input valve, operatively
coupled to said cold-side input, and operatively coupled to said
pump; and k) a hot water output valve operatively coupled to the
output from the hot-side, and operatively coupled to said pump;
wherein said programmable control module and valves are further
adapted to automatically form a descaling circuit between the
hot-side, the pump, the cold-side and the internal flow of the
water heating unit during a descaling operation, and said
programmable control module and valves are further adapted to
automatically form rinsing circuit between the potable water input,
the cold-side, the internal flow of the water heating unit, the
hot-side and a rinse discharge valve during a rinsing
operation.
11. The system of claim 8, wherein said programmable control module
and valves are further adapted to automatically disable the
descaling and rinsing circuits during normal operation mode.
12. The system of claim 8, further comprising: a solenoid
operatively coupled to each said valve.
13. The system of claim 12, wherein said programmable control
module is adapted to output control signals operatively coupled to
said solenoids, for energizing and de-energizing said solenoids,
and for opening and closing an associated valve according to the
signal received.
14. The system of claim 12, further comprising: a power relay
operatively coupled to said solenoids and operatively coupled to
said programmable control module, said power relay adapted to cause
said solenoids to energize and de-energize in response to
activation from said programmable control module.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims the priority of U.S.
Provisional Patent Application Ser. No. 61/585,956, filed Jan. 12,
2012 for "Method and Device for Automatic Descaling of Tankless
Water Heaters."
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention generally relates to the field of
water heaters and water heating systems, with emphasis on the
tankless variety, and particularly relates to the maintenance of
said heaters and systems.
[0004] 2. Background
[0005] Tankless or on-demand water heaters are rapid-response water
heaters that represent advances over conventional "tank" water
heaters, including energy and space savings.
[0006] The major components of a conventional tankless water heater
are illustrated with reference to FIG. 1. In the tankless water
heater 100, a control module serves to electronically control the
operation of the unit. Tankless water heaters have similar make-up
whether they are larger units designed to supply hot water to an
entire structure such as a home or other building, or whether they
are smaller units designed to supply hot water to a limited area
such as an individual sink or bathroom shower.
[0007] In operation, cold, potable water enters the unit 100 via an
input 120 to a valve 130, which may optionally contain an emergency
shut-off and diverter feature to divert water from the unit if the
unit is in a "lock-out" condition. The "lock-out" condition shuts
the unit down to protect it from highly inefficient or unsafe
operating conditions. Without diversion of the water source, water
from the "hot water" designated piping will not flow in the
structure.
[0008] A flow sensor 160 senses the flow of water coursing through
the supply line (i.e., a demand for hot water has been triggered by
turning on a hot water faucet or the like) and sends a signal to
the control module 110. In response, the control module 110
activates a heat exchanger 170 for rapid heating of the water,
whereupon the heated water exits the unit 100 via an output valve
140 and output 150 (toward the hot water demand site in the
structure). A heat sensor 180 monitors the heat exchanger
temperature and a water temperature sensor temperature of the water
leaving the unit.
[0009] If the heat exchanger 170 overheats, the control module 110
causes it to shutdown. Large discrepancies between the heat
exchanger temperature and the water temperature immediately leaving
the heat exchanger can also indicate inefficient or unsafe
operating conditions. Either may cause a "lock-out" condition,
which will typically also send a visible error signal viewable via
a control panel display (not shown).
[0010] "Hard" water (or mineral-rich water) poses challenges to the
efficient and safe operation of hot water heaters, as mineral
deposits, often in the form of calcium or lime scale build-up
attach to both heating surfaces and conduits. And while the greater
movement of water in the aggregate of tankless water heaters may
lead to a reduction of scale build-up, compared to convention tank
units, scale build-up is nonetheless a problem. Scale deposit
build-up is observed in tankless water heater units over time even
where "softer" potable water is used. Therefore, tankless water
heater units need to be periodically descaled for efficient and
safe operation. Because of their higher initial costs, it is not
economical to discard tankless water heaters with the same
frequency as lower-cost tank heaters when scale build-up
occurs.
[0011] The primary prior art approach to descaling tankless water
heaters, is a manually one where a service person decouples the
unit from the supply and output lines and forces a descaling
cleaning solution through the tankless unit conduits to remove the
scale build-up. The cleaning solution and any scale build-up
collected in the process are purged from the system. The process is
repeated as needed. Unfortunately for tankless water heater unit
owners, the manual descaling process can be expensive (for labor
costs and the costs attributable to a portion of expensive,
special-purpose descaling equipment) and inconvenient, as well as
disruptive of hot water peak demand time.
[0012] The other prior approach is to install scale inhibition
filters that reduce scale build-up. However, this only delays the
inevitable by relative slight times, and can be costly over time as
well.
[0013] The typical tankless water heater unit requires thorough
descaling once or twice a year. Thus, there is a long-standing, but
unmet and unsolved need to provide tankless water heaters and
tankless water heating systems that do not require labor-intensive
descaling, as the prior art uniformly teaches and suggests
labor-intensive descaling approaches. There is also a
long-standing, but unmet and unsolved need to meaningfully reduce
descaling costs over the life of tankless water heaters and
tankless water heating systems.
SUMMARY OF THE INVENTION
[0014] In response to the long-felt, but unsolved and unmet needs
of the prior art the present invention provides a novel method of
descaling a water heating unit, the water heating unit being
adapted to receive unheated, potable water via a cold-side input,
and adapted to output heated water to the demand destination via a
hot-side output. The method at least includes: a) operating a water
heating unit in a normal mode as a default; b) via a programmable
control module, selectively receiving a user-defined descaling
operation start date and time; c) via the programmable control
module, monitoring for the advent of the descaling operation start
date and time; d) via the programmable control module, and upon the
arrival of the descaling operation start date and time,
automatically shutting off the supply of heated water to the demand
destination, and automatically activating a pump; e) via said pump,
automatically pumping a stored descaling solution through said
water heating unit via said cold-side input of said water heating
unit and said hot-side output of said water heating unit to
dislodge scale deposits from said water heating unit; f) via said
pump, automatically rinsing said water heating unit to remove
dislodged scale deposits and to remove descaling solution; g)
discharging dislodged scale deposits and descaling solution from
said water heating unit; h) restoring the supply of heated water to
the demand destination; and i) returning the water heating unit to
normal operation mode.
[0015] The present invention also provides a novel system for
descaling a water heating unit, said water heating unit being
adapted to receive unheated, potable water via a cold-side input,
and adapted to output heated water to the demand destination via a
hot-side output, which water heating unit operates in a normal mode
as a default. The system at least includes: a pump; a descaling
solution source; a plurality of valves; a programmable control
module operatively coupled to said pump, said descaling solution
source, and said valves, said programmable control module adapted
to selectively receive a user-defined descaling operation start
date and time, monitor for the advent of the descaling operation
start date and time, and upon the arrival of the descaling
operation start date and time, automatically shut off via at least
one valve, the supply of heated water to the demand destination,
and automatically activate said pump; said pump adapted to
automatically pump stored descaling solution through said water
heating unit via said cold-side input of said water heating unit
and said hot-side output of said water heating unit to dislodge
scale deposits from said water heating unit, and further adapted to
automatically rinse said water heating unit to remove dislodged
scale deposits and to remove descaling solution; and said
programmable control module further adapted to cause said valves to
discharge dislodged scale deposits and descaling solution from said
water heating unit, restore the supply of heated water to the
demand destination, and return said water heating unit to normal
operation mode.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0016] Features and advantages of the present invention will become
apparent to those skilled in the art from the description below,
with reference to the following drawing figures, in which:
[0017] FIG. 1 is a schematic diagram of a prior art tankless water
heater unit;
[0018] FIG. 2 is a general schematic diagram of the
present-inventive automatic water heater descaling system and
apparatus;
[0019] FIG. 3 is a schematic diagram of the present-inventive
automatic water heater descaling system and apparatus showing the
state of the conduits (solid lines for open; dotted lines for
closed) when the tankless unit is operating in the normal mode;
[0020] FIG. 4 is a schematic diagram of the present-inventive
automatic water heater descaling system and apparatus of FIG. 3,
showing the state of the conduits (solid lines for open; dotted
lines for closed) during cleaning mode when the tankless unit is
undergoing descaling;
[0021] FIG. 5 is a schematic diagram of the present-inventive
automatic water heater descaling system and apparatus of FIG. 3,
showing the state of the conduits (solid lines for open; dotted
lines for closed) during rinse mode when the tankless unit is
undergoing rinsing after descaling; and
[0022] FIG. 6 is a flowchart illustrating the present-inventive
automatic water heater descaling process as can be carried out by
(but not limited to) the system and apparatus of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] FIG. 2 illustrates the general architecture of the preferred
embodiment of the present-inventive system 200 capable of
implementing the present-inventive method for automatically
descaling a water heating unit--in this case a tankless (or
on-demand) water heating unit 100. An automatic descaler 204
directly carries out the descaling and rinsing operations with
respect to the water heater 100. As will be described below, the
system 100 novelly monitors for a triggering date and time which
the user may program to trigger an automated descaling operation to
descale (i.e., remove scale deposits from the conduits, including
the heat exchanger) the water heater 100. In the preferred
embodiment, the descaling operation is followed by an automated
rinsing operation for rinsing away dislodged scale deposits along
with the descaling solution and any other by-products of chemical
reactions during the descaling process. While the descaling and
rinsing operations occur, the water heater is automatically
decoupled from the hot water supply line to the structure.
Likewise, when the descaling and rinsing operations are complete,
the water heater is re-coupled to the hot water supply line to
supply heated, potable water to the structure. The automatic
descaler 204 and water heating unit 100 are supplied with
alternating current (A.C.) power as will be appreciated by those
skilled in the art.
[0024] The automatic descaler 204 can be constructed as a
stand-alone unit for directly coupling to the water heater inputs
and outputs. Alternatively, systems 200 can be manufactured as one
unit that includes both the automatic descaler and the water
heater.
[0025] The heart of the automated processes and the automatic
descaler 204 is a programmable control module 208, which both
receives programmable data from a user who enters a desired date
and time for a future or future descaling operations to occur, and
monitors and directs the automated descaling and rinsing processes.
Those skilled in the art will appreciate that given the present
description, the programmable control module may take many forms,
including a more generally programmable computing device at the
high end, and a state machine on the low end. All of the major
conduits appear as thick solid lines in FIG. 2 for illustrative
purposes. In subsequent drawing figures, solid conduit lines
represent open conduits that allow flow, while dotted conduit lines
represent closed conduits that do not allow flow.
[0026] The other major components of the automatic descaler 204 are
a cleaning/descaling solution tank 212 for storing and then
delivering a cleaning/descaling solution during a
cleaning/descaling operation, a pump 216 for pumping
cleaning/descaling solution to and through the water heater during
a cleaning/descaling operation, a power supply 220 for supplying
appropriate types and levels of electrical power to the elements of
the automatic descaler 204, and several solenoid-triggered valves
228, 232, 236, 240 and 244, for directing the flow of potable water
and cleaning/descaling solution, from, through and away from the
water heater during normal operation, and during cleaning/descaling
and rinsing operations. A power relay 224 coupled to the power
supply 220 and the valves (connections not shown) triggered by the
programmable control module 208, sends power to the valve solenoids
to energize the solenoids (and thus open a normally closed valve,
or close a normally open valve) during cleaning/descaling and
rinsing operations.
[0027] The automatic descaler 204 connects to the cold side 120 and
hot side 150 of the tankless water heater 100. The additional major
components of the system 200 include a potable water input 248 for
receiving potable water to be heated and supplied to the structure,
a rinse discharge output 252 for outputting discharged scaling
deposits, descaling solution, and rinsing water during an automated
rinse operation, and a hot water output 256 for outputting heated,
potable water to target structure (i.e., house or building).
[0028] FIG. 3 illustrates the state of the automatic descaler 204
during the normal operation of the water heater 100. In the normal
mode of operation of the water heater 100, the automatic descaler
204 effectively acts as a pass-through valve that passes unheated
potable water directly to the water heater 100 to be heated, and
passes heated, potable water directly from the water heater 100 to
the structure or targeted location in the structure. In their
default states, which correspond to the normal mode of operation of
the water heater, valves 232 and 240 are normally open, while
valves 228, 236, and 244 are normally closed. The programmable
control module 208 continues to monitor for the date and time
designated for a scheduled cleaning/descaling operation.
[0029] When the programmable control module 208 detects the date
and time for a scheduled descaling operation, it causes the
appropriate solenoids to change the states of their associated
valves as needed, and as shown in FIG. 4. The water heater 100 is
taken off-line (from the structure supply line) during the
cleaning/descaling and rinse operations. The AC power supplied to
the water heater via the power relay 224 during normal operation
mode is also removed. In particular, during cleaning/descaling
mode, normally open valves 240 and 228 leading to the potable water
input 248 and hot water output 256, respectively, are automatically
closed. Normally closed valves 236 and 244 are energized to open,
while valve 228 remains closed. By these actions a closed fluid
circuit is formed between the water heater 100, the
cleaning/descaling solution tank 21, and the pump 216 during
cleaning/descaling mode.
[0030] During the cleaning/descaling mode the pump 216 circulates
cleaning/descaling solution from the cleaning/descaling solution
tank 212 through the water heater 100 for a predetermined time to
remove scale deposits from the fluid conduits of the water heater.
The cleaning/descaling operation may last for a default length of
time (e.g., 20 minutes) or other length of time programmable by the
user. While the system 200 is in cleaning/descaling mode, the
programmable control module 208 monitors for the scheduled onset of
the rinsing mode/cycle.
[0031] When the rinsing mode is triggered, the state of the
conduits is as shown in FIG. 5. The hot water heater remains
off-line to the structure (valve 232 remains closed), but the cold
side 120 receives potable water via the newly opened valve 240.
Previously open valves 236 and 244 are closed to move the pump 216
and tank 212 off-line. The pressured potable water rinses the
conduits of the water heater 100, while a newly opened rinse
discharge vale 228 discharges the by-products of the rinsing
operation from the heater. The discharge may be directed to a water
drain or the like. The rinsing mode may last for a default length
of time (e.g., 5 minutes) or other length of time programmable by
the user. The programmable control module 208 monitors for the
scheduled return to normal operation mode of the water heater
100.
[0032] When normal operation mode is triggered, the state of the
automatic descaler 204 returns to settings illustrated in FIG. 3.
That is, previously open valve 228 is closed; previously closed
valve 232 is opened; valve 240 remains open; and valves 236 and 244
remain closed. The water heater 100 is now on-line to supply
heated, potable water to the structure per its normal operation.
The programmable control module 208 continues to monitor for a
scheduled cleaning/descaling operation. Automatic
cleaning/descaling operations can be scheduled as frequently or
infrequently as desired by the user, or in accordance with default
dates and times. Typical automatic cleaning/descaling operations
might, however, occur twice a year.
[0033] Turning to FIG. 6, the present-inventive method 600 for
automatic descaling of water heating units is illustrated by way of
a flowchart. At the starting Step 604 of the process, the
programmable control module 208 monitors a cleaning/descaling mode
timer which has been programmed to provide a count up to (or down
to) a moment in time representing the date and starting time for a
scheduled cleaning/descaling operation. If the cleaning/descaling
mode timer count has been reached, the decision Step 608 advances
the process to Step 616. If not, the process is returned to Step
612 to continue to keep valves 232 and 240 open, and continue to
keep valves 228, 236 and 244 closed during normal operation of the
water heater.
[0034] Step 616 begins a cleaning/descaling operation and sets the
value of a cleaning/decaling cycle timer (in accordance with the
predetermined cleaning/descaling operation duration), which begins
to count up (or down). This is followed by the closing of valves
232 and 240, and the opening of valves 236 and 244, while valve 228
remains closed (Step 620). Power to the water heater is also
removed during the cleaning/descaling operation, as well as during
the rinsing operation. In Step 624, the pump 216 is activated to
circulate cleaning/descaling solution through the water heater and
back through the automatic descaler 204. The cleaning/descaling
operation continues until the stored cleaning/descaling cycle count
is reached (Step 628), whereupon the process advances to Step
632.
[0035] Step 632 begins a rinsing operation and sets the value of
rinsing cycle timer (in accordance with the predetermined rinsing
operation duration), which begins to count up (or down). This is
followed by the closing of valves 236 and 244, and the opening of
valves 228 and 240, while valve 232 remains closed (Step 636). In
Step 640, the water heating unit 100 is internally rinsed and
discharged via valves 240 and 228 as described supra. The rinsing
operation continues until the stored rinsing cycle count is reached
(Step 644), whereupon the process advances to Step 648.
[0036] Step 648 returns the process to normal operation mode where
the water heater supplies heated, potable water to the structure.
In this step, the cleaning/descaling timer is set to a
predetermined value corresponding to the next scheduled
cleaning/descaling operation, and the timer is activated.
Meanwhile, valve 228 is closed, valve 232 is opened, valve 240
remains open, and valves 236 and 244 remain closed. Power is also
restored to the water heater. The automated process returns to the
beginning Step 604.
[0037] Variations and modifications of the present invention are
possible, given the above description. However, all variations and
modifications which are obvious to those skilled in the art to
which the present invention pertains are considered to be within
the scope of the protection granted by this Letters Patent. For
example, while the present-inventive automatic descaling system and
method have been primarily discussed with respect to tankless water
heating units, the teachings may be applied to convention tank
water heating units.
* * * * *